The present invention relates to a system for measuring a quantity of compressed gas supplied under high pressure from a first tank to a second tank.
Such systems are known in various forms and incorporated in numerous technical applications. In some such applications, there exists a need to bill for the quantity (i.e. volume) of gas supplied which requires not only a determination of the quantity of gas under the conditions of supply (e.g. temperature and pressure) but also that the quantity should be determined under uniform, standard conditions (also referred to herein as "normal") with respect to pressure and temperature regardless of the conditions of supply.
A type of gas meter is known which is provided with mechanical or electronic temperature and pressure correctors that serve to convert the quantity of gas, as supplied, to standard conditions, such as atmospheric pressure. This type of gas meter is commonly called a PTZ type, with the P and the T representing pressure and temperature, respectively, and the Z representing gas constituent variables which, for example, can vary from city to city. The correctors used in such PTZ meters are complex and expensive. The accuracy desired, such as for billing, determines the complexity of the prior art PTZ gas meters. In practice, it is necessary to choose between greater billing accuracy at the cost of using a sophisticated meter on the one hand, and using a simple meter at the expense of less accurate billing on the other hand.